Unsaturated derivatives of polyhydric phenols are a well known class of compounds that can be cured or crosslinked to produce insoluble products that typically exhibit good solvent resistance and mechanical propertis as well as relatively high heat distortion temperatures. Such unsaturated derivatives are crosslinked by reaction with catalytic or polyfunctional stoichiometric curing agents to produce tough, heat resistant products which are processed by conventional methods into films or laminates with fiber glass or other reinforcements or into shaped objects and the crosslinked products are additionally useful in adhesive formulations.
When the unsaturated phenolic derivative is an ether of a polyhydric phenol, or is produced from a polyhydric phenol, much of the technology is broadly conventional. The phenolic ether is suitably cured or crosslinked as such but additionally the ether is rearranged to produce a phenol having an unsaturated ortho substituent (occasionally para), which phenol is also curable. The disclosure of Zahir, U.S. 4,100,140, is illustrative. The compound 2,2-di(4-hydroxyphenyl)propane, also known as bisphenol A or BPA, is converted to its sodium salt and reacted with allyl chloride to produce the diallyl ether of BPA, i.e., 2,2-di(4-allyloxyphenyl) propane. This diallyl ether is curable, for example, by heating the diallyl ether with an imide-containing curing agent. Alternatively, the diallyl ether is subjected to rearrangement according to the classical Claisen Rearrangement to produce the corresponding ortho-allylphenol, i.e., 2,2-di(4-hydroxy-3-allylphenyl)propane. The ortho allyl derivative is also curable as by heating with a bis(maleimide). It is also known to produce an allyl ether of the ortho-allylphenol and subsequently conduct a second rearrangement to produce an o,o-diallylphenol derivative. To obtain even greater functionality, an allyl ether of the diallylphenol is produced, all by conventional technology.
On some occasions, the cured products which provide the more desirable properties, particularly in high temperature applications, are those wherein the phenolic derivatives are of polycyclic structure. It would be of advantage to provide a novel class of unsaturated derivatives of phenols having a plurality of rings within the molecular structure.